PR c++/91370 - Implement P1041R4 and P1139R2 - Stronger Unicode reqs

	PR c++/91370 - Implement P1041R4 and P1139R2 - Stronger Unicode reqs
	* charset.c (narrow_str_to_charconst): Add TYPE argument.  For
	CPP_UTF8CHAR diagnose whenever number of chars is > 1, using
	CPP_DL_ERROR instead of CPP_DL_WARNING.
	(wide_str_to_charconst): For CPP_CHAR16 or CPP_CHAR32, use
	CPP_DL_ERROR instead of CPP_DL_WARNING when multiple char16_t
	or char32_t chars are needed.
	(cpp_interpret_charconst): Adjust narrow_str_to_charconst caller.

	* g++.dg/cpp1z/utf8-neg.C: Expect errors rather than -Wmultichar
	warnings.
	* g++.dg/ext/utf16-4.C: Expect errors rather than warnings.
	* g++.dg/ext/utf32-4.C: Likewise.
	* g++.dg/cpp2a/ucn2.C: New test.

From-SVN: r277929

2 files changed, 22 insertions, 5 deletions

diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 8be84386d6c..b57f26584a1 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,14 @@
+2019-11-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/91370 - Implement P1041R4 and P1139R2 - Stronger Unicode reqs
+	* charset.c (narrow_str_to_charconst): Add TYPE argument.  For
+	CPP_UTF8CHAR diagnose whenever number of chars is > 1, using
+	CPP_DL_ERROR instead of CPP_DL_WARNING.
+	(wide_str_to_charconst): For CPP_CHAR16 or CPP_CHAR32, use
+	CPP_DL_ERROR instead of CPP_DL_WARNING when multiple char16_t
+	or char32_t chars are needed.
+	(cpp_interpret_charconst): Adjust narrow_str_to_charconst caller.
+
 2019-11-05  Tim van Deurzen  <tim@kompiler.org>
 
 	* cpplib.h: Add spaceship operator for C++.
diff --git a/libcpp/charset.c b/libcpp/charset.c
index 39af77a554a..0b8815af46b 100644
--- a/libcpp/charset.c
+++ b/libcpp/charset.c
@@ -1881,10 +1881,11 @@ cpp_interpret_string_notranslate (cpp_reader *pfile, const cpp_string *from,
 /* Subroutine of cpp_interpret_charconst which performs the conversion
    to a number, for narrow strings.  STR is the string structure returned
    by cpp_interpret_string.  PCHARS_SEEN and UNSIGNEDP are as for
-   cpp_interpret_charconst.  */
+   cpp_interpret_charconst.  TYPE is the token type.  */
 static cppchar_t
 narrow_str_to_charconst (cpp_reader *pfile, cpp_string str,
-			 unsigned int *pchars_seen, int *unsignedp)
+			 unsigned int *pchars_seen, int *unsignedp,
+			 enum cpp_ttype type)
 {
   size_t width = CPP_OPTION (pfile, char_precision);
   size_t max_chars = CPP_OPTION (pfile, int_precision) / width;
@@ -1913,10 +1914,12 @@ narrow_str_to_charconst (cpp_reader *pfile, cpp_string str,
 	result = c;
     }
 
+  if (type == CPP_UTF8CHAR)
+    max_chars = 1;
   if (i > max_chars)
     {
       i = max_chars;
-      cpp_error (pfile, CPP_DL_WARNING,
+      cpp_error (pfile, type == CPP_UTF8CHAR ? CPP_DL_ERROR : CPP_DL_WARNING,
 		 "character constant too long for its type");
     }
   else if (i > 1 && CPP_OPTION (pfile, warn_multichar))
@@ -1980,7 +1983,9 @@ wide_str_to_charconst (cpp_reader *pfile, cpp_string str,
      character exactly fills a wchar_t, so a multi-character wide
      character constant is guaranteed to overflow.  */
   if (str.len > nbwc * 2)
-    cpp_error (pfile, CPP_DL_WARNING,
+    cpp_error (pfile, (CPP_OPTION (pfile, cplusplus)
+		       && (type == CPP_CHAR16 || type == CPP_CHAR32))
+		      ? CPP_DL_ERROR : CPP_DL_WARNING,
 	       "character constant too long for its type");
 
   /* Truncate the constant to its natural width, and simultaneously
@@ -2038,7 +2043,8 @@ cpp_interpret_charconst (cpp_reader *pfile, const cpp_token *token,
     result = wide_str_to_charconst (pfile, str, pchars_seen, unsignedp,
 				    token->type);
   else
-    result = narrow_str_to_charconst (pfile, str, pchars_seen, unsignedp);
+    result = narrow_str_to_charconst (pfile, str, pchars_seen, unsignedp,
+				      token->type);
 
   if (str.text != token->val.str.text)
     free ((void *)str.text);